Due to the similar naming logic, the preset for configuring optimal
debugging output conflicts with the ApplicationContext set as an
environment variable (TYPO3_CONTEXT), is changed from
"Production" and "Development" to "Live" and "Debug".

The patch resolves quite some mess in ext:rtehtmlarea
around the localization files. Many files are moved around
and some are deleted (ok with localization team). Some
internal methods are adapted a bit.

[BUGFIX] Only count items in ForViewHelper when ``iteration`` argument is set

When using the ``iteration`` argument, the ``ForViewHelper`` provides
information about the current iteration, including the ``cycle`` and
``total``. Therefore it needs to count all elements.
The problem is, that this happens even if the iteration argument is
not specified leading to performance issues especially when iterating
over a (subset of a) lot of (remote) items.

This patch fixes this by adding a check for the ``iteration`` argument.

Previously classes for extensions that were not loaded,
were also not autoloadable. To simplify composer installation
of the core, we now include autoload information of all extensions
that are delivered with the typo3/cms package.

By doing so, authors of distribution composer.json files
do not need to amend it with class loading information of
core extensions any more.

This means that class loading information for every
system extension will be written to typo3/contrib/vendor
by the packaging script, so that we do not need to respect
these when building additional autoload information for extensions
that are installed via the extension manager in a non composer
managed environment.

The default lifetime of frontend related rootline cache is
only one hour, raising query load in production. This is
raised to 30 days now - same as cache_pagesection.
The rootline cache entries are tagged with pageId_* and
in cache group "pages", so the DataHandler automatically
drops those entries if pages are moved around or change.

Race conditions can occur when the cache in typo3temp/Cache gets
cleared, for example by using the Install Tool "Clear all caches"
button. The cache is currently cleared using GeneralUtility::rmdir()
which does a directory traversal and unlinks all contained files.
Instead GeneralUtility::flushDirectory() should get used. This method
renames the directory into a temp-dir name and then removes the temp-dir
using GeneralUtility:rmdir().

AbstractExceptionHandler still used a formerly public property which
has been defined as protected in the meantime.
Cleaning up the code and using a getter method for access of $GLOBALS
revealed the issue.

* editorCSS is not used on JS side, so removed
* Plugin API requiresClassesConfiguration() has some
regular plugins that are nearly always enabled and
set this to TRUE, which triggers as call of
buildJSClassesConfig(). This method is now just
always called and the "requireClasses" stuff removed.
* getPathToPluginDirectory() was only used together with
the "requireClasses" construct and is removed as
logical follow-up.

The global variable FILEICONS was used before there were
sprite icons for files prior to TYPO3 v4.4.

The $FILEICONS array is still filled on every request but
never used throughout the backend. The only usage
within BackendUtility::getFileIcon() is also never used
and thus is completely removed from the TYPO3 Core.

[TASK] Change clipboard drop down from splitted button to single button

This patch changes the style for the drop down menu from one splitted
button to on single button. This is because the splitted button only
reacts on a click on the caret, which is a unwanted behaviour.